Surface quality of carbon/carbon composite after ultrasonic assisted turning

Author(s):  
F J Ma ◽  
D M Guo ◽  
R K Kang ◽  
Y J Ren

It is usually hard to obtain a good surface quality of carbon/carbon (C/C) composite by turning due to its non-homogeneity and anisotropy. Contrasting experiments of ultrasonic assisted turning (UAT) and common turning (CT) of the C/C composite were carried out using a polycrystalline diamond tool. The cylindrical surface of the turning was classified into four typical types based on different fibre orientations. The influence of fibre distribution characteristics on surface roughness was analysed by measuring and comparing the roughness of these surfaces, and an evaluation method of surface quality for the C/C composite after turning was established. The results of UAT experiments on the C/C composite show that UAT could effectively reduce the machining defect. The roughness of typical surfaces 1 and 2 machined using UAT was about 20 per cent lower than that using CT.

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 519-527
Author(s):  
Wei Gong ◽  
Xianglin Pei ◽  
Xiaogang Yin ◽  
Daming Ban ◽  
Hai Fu ◽  
...  

AbstractIn this paper, acrylonitrile and hydroxypropyl acrylate are used as the binary polymerization monomers, and isooctane is used as the foaming agent to prepare high-temperature thermally expandable microcapsules. Analysis of the effect of blowing agent and crosslinking agent on the expansion properties of high-temperature thermally expandable microcapsules, the effects of foaming agent azodicarbonamide (ADCA) and micro-expansion capsule on the surface quality and foaming quality of foamed acrylonitrile–butadiene–styrene (ABS) products were investigated. The foamed product prepared by the high-temperature microcapsule has a good surface quality, the gloss is 52.3, the cell is not easily deformed, and the volume fraction is 4%; the foamed ABS/ADCA material has poor cell uniformity, the cell is easily deformed, the volume fraction is 6.5%, the surface quality is poor, and the gloss is only 8.7.


Laser Physics ◽  
2020 ◽  
Vol 30 (11) ◽  
pp. 116202
Author(s):  
Zhangfan Wei ◽  
Qiao Yuan ◽  
Aijun Zeng ◽  
Huijie Huang ◽  
Sergey Avakaw

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Juha Huuki ◽  
Mikael Hornborg ◽  
Jermu Juntunen

This paper presents ultrasonic burnishing as a mechanical surface treatment for improving the quality of rotating shafts. Ultrasonic burnishing is a modern method for finishing workpieces to produce a good surface quality. This process improves the surface quality and increases the surface hardness of the workpiece, and the surface roughness of the workpiece improves. As a result, wear resistance and fatigue life increase. Furthermore, these improvements are achieved without expensive equipment or long processing times. In this paper the influence of the ultraburnishing technique on the change in diameter and its effects on the out-of-roundness of rotating shafts are investigated. This paper also takes a look at the magnitudes of the improvement of the surface roughness as a result of using ultrasonic burnishing. Three different materials, aluminium, 34-CrNiMo6 tempering steel, and S355J2 structural steel, are examined. The results showed that ultrasonic burnishing is a treatment that improves the quality of components. Ultrasonic burnishing also has a reducing effect on the final diameter and out-of-roundness and increases the hardness of the workpiece. It can also be stated that the material of the workpiece does not have a significant effect on the magnitude of the reduced surface roughness values.


2010 ◽  
Vol 97-101 ◽  
pp. 382-385 ◽  
Author(s):  
Jun Tao Guan ◽  
Le Hua Qi ◽  
Li Zheng Su ◽  
Jian Liu

10vol. % Csf/AZ91D composites were fabricated by extrusion following vacuum infiltration process with self-developed experimental device and measuring system. The relationships of load vs displacement during process and surface quality of composites at various extrusion temperatures were investigated. SEM microscope was used to observe the microstructure of fabricated composites. The experimental results showed that the extrusion process can be divided into three deformation stages. The extrusion temperature had a great influence on the maximum extrusion load. Based on proper infiltration parameters, a extruded bar with good surface quality was obtained at extrusion temperature of 420°C.


2020 ◽  
pp. 1-11
Author(s):  
Huang Wenming

The efficiency of traditional English teaching quality evaluation is relatively low, and evaluation statistics are very troublesome. Traditional evaluation method makes teaching evaluation a difficult project, and traditional evaluation method takes a long time and has low efficiency, which seriously affects the school’s efficiency. In order to improve the quality of English teaching, based on machine learning technology, this study combines Gaussian process to improve the algorithm, use mixed Gaussian to explore the distribution characteristics of samples, and improve the classic relevance vector machine model. Moreover, this study proposes an active learning algorithm that combines sparse Bayesian learning and mixed Gaussian, strategically selects and labels samples, and constructs a classifier that combines the distribution characteristics of the samples. In addition, this study designed a control experiment to analyze the performance of the model proposed in this study. It can be seen from the comparison that this research model has a good performance in the evaluation of the English teaching quality of traditional models and online models. This shows that the algorithm proposed in this paper has certain advantages, and it can be applied to the practice of English intelligent teaching system.


2017 ◽  
Vol 9 (2) ◽  
pp. 168781401769354 ◽  
Author(s):  
Dao-hui Xiang ◽  
Zhong-yun Liu ◽  
Zhi-kun Zhou ◽  
Yun-long Yao

The kinematic characteristics, grinding force, surface quality of workpiece surface, and wear of abrasive particles were studied by theoretical analysis and experimental study on the single cubic boron nitride abrasive particles under ultrasonic-assisted high-speed grinding. Under the condition of the same grinding parameters, the motion characteristics and the grinding forces of the two machining modes of general grinding and ultrasonic-assisted grinding are compared and analyzed. Research shows that the ultrasonic vibration is applied in the common external circular grinding on grinding particle movement characteristics changed obviously, grinding particle trajectory of variable length, cutting groove width wider, thereby improving the grinding efficiency and the grinding removal rate; ultrasonic assisted under high speed grinding, the grinding force is higher than that of common grinding force is small, efficiency of grinding under ultrasonic processing mode is much higher than ordinary grinding, the surface quality of the workpiece has improved markedly.


2013 ◽  
Vol 797 ◽  
pp. 338-343 ◽  
Author(s):  
Vitchuda Lertphokanont ◽  
Takayuki Sato ◽  
Minoru Ota ◽  
Keishi Yamaguchi ◽  
Kai Egashira

Whirling Electrical Discharge Texturing (WEDT) was developed to create microstructures. It was thought that textured surface with low surface roughness could reduce friction coefficient on the sliding parts. In this research, surface quality was studied to evaluate the quality of WEDT textured surface. Surface quality was evaluated in terms of the surface roughness and surface integrity which were characterized by microstructure, composition and residual stress of the textured surface. The value of Rp and Rv of textured surface after finishing with improved finishing method were obtained as expected for low surface roughness to reduce friction coefficient. In addition, it was clarified that microstructure and composition of textured surface after texturing with WEDT and finishing with lapping-film depend on feed speed. Furthermore, the compressive residual stress was presented on WEDT textured surface and depended on feed speed. It was confirmed that good surface quality of textured surface could be obtained by WEDT.


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